US Central Command chief Kenneth McKenzie pledged Thursday to work “aggressively” with partners to ensure freedom of navigation in Gulf waters.

But the Guards’ deputy chief said the United States will soon realise “it is not in its interest at all to stay in the region”.

US forces are under mounting “psychological pressure” in the Gulf, Brigadier-General Ali Fadavi was quoted by Tasnim as saying.

The drone incident comes amid a threatened breakdown of the 2015 Iran nuclear deal, with Washington steadily ratcheting up economically debilitating sanctions on Tehran a year after unilaterally quitting the deal.

Earlier this month, Tehran purposely surpassed the deal’s caps on uranium enrichment, aiming to pressure the remaining parties to make good on their promises to support Iran economically.

Iran has repeatedly threatened to close the Strait of Hormuz if Tehran’s oil exports are blocked through sanctions.

Last month Oil Minister Bijan Namdar Zanganeh said Iran was keeping up sales through “unconventional” means to circumvent the US measures.